Schematically, a luminous panel comprises an array of luminous elements, or pixels, individually controlled by an array of control circuits (or “active array”). Each control circuit comprises, to drive its associated pixel, one or a plurality of transistors, operating as switches, and most often a capacitor for maintaining the pixel biasing between two refreshments of the panel display.
To date, only two technologies enable to form luminous panels having large dimensions and a long lifetime, that is, the liquid crystal-based technology (“LCD”), and the plasma-based technology (“plasma” display panel). Each of these technologies however has a number of disadvantages, for example, a problem of power efficiency and of directivity for LCDs, and a problem of power consumption and of screen burn-in for plasma display panels.
Alternative technologies, particularly based on organic photodiodes (or “OLED”), have thus been developed, without however providing a satisfactory result. Indeed, OLED-based displays exhibit shine issues and have too short a lifetime, limiting their use to devices considered as having a short lifetime (particularly, smartphones).
In parallel, whatever the technologies envisaged for light generation (LCD, plasma, OLED, . . . ), the control circuits are manufactured in thin film deposition technology, called “TFT” (“thin film transistor”). The electronic components of the control circuits (particularly transistor(s), capacitor, electric tracks) are thus formed by successively depositing thin films of material and by using photolithography masks to delimit their components (electrodes, semiconductor layer, dielectric layer, tracks . . . ). For example, the manufacturing of the control circuits of an LCD, each only comprising one transistor and one capacitor, requires using from 5 to 9 photolithography masks. The cost of the control circuits manufactured according to this technology is thus very high. Further, the manufacturing of an active array of large dimension according to the conventional TFT technology substantially increases the cost of a screen due to the cost of the equipment enabling to deposit thin films on large surface areas. This is why it is estimated that only a few market operators, capable of investing in high-cost equipment, are now capable of bearing their cost.